2010 was a transformative year for the U.S. effort in Afghanistan, with 30,000 additional troops and thousands more civilians flowing into the country to implement President Barack Obama's revised strategy for winning the now nine-year-old war.

It has been a difficult and deadly year in the Afghanistan war. Violence and casualties are up. And progress has been difficult to measure.

But U.S. Defense Secretary Robert Gates was optimistic during his most recent visit to Afghanistan in December. "The bottom line is that in the last 12 months we have come a long way, frankly progress that even just in the last few months has exceeded my expectations," he said.

But Gates also acknowledged that progress in some areas, where U.S., allied and Afghan efforts have been focused, does not mean there is progress toward stability, security and prosperity elsewhere in the country. "The lesson learned here is that you should not generalize about Afghanistan. You should not even generalize from regional command to regional command or province to province, that you really have to take it a district at a time, and maybe even more local areas than that," he said.

Announcing the results of the year-end Afghanistan policy review on December 16th, President Obama said progress is being made and the strategy of using the military to pursue hard-core insurgents and train Afghan forces, and using international civilians to help improve governance and promote economic development, is working.

"This continues to be a very difficult endeavor. But I can report that thanks to the extraordinary service of our troops and civilians on the ground, we are on track to achieve our goals," he said.

The president called the progress "fragile and reversible," and his review calls for more efforts to establish local security in key areas, and to press Pakistan to take more action against insurgent bases on its side of the border.

It was not a smooth road for President Obama to get to his year-end review. "Today I accepted General Stanley McChrystal's resignation as commander of the International Security Assistance Force in Afghanistan," he said.

That was June 23, just a year after the president had appointed General McChrystal to command the U.S. and NATO military effort in Afghanistan, only six months after the president had finalized his strategy, and well before most of the additional troops had even arrived. He fired McChrystal for critical comments about the president, his policy, and his aides made by the general and members of his staff in a Rolling Stone magazine article.

Within a fast and wrenching 48 hours, the general who had been built up as the best man to win the war in Afghanistan was gone. But the president did not have to look far to find a suitable successor. "I am also pleased to nominate General David Petraeus to take command in Afghanistan, which will allow us to maintain the momentum and leadership that we need to succeed," he said.

General Petraeus was McChrystal's boss, commander of all U.S. forces in the Middle East and Central Asia, and the famed former commander of allied troops in Iraq credited with developing the counter-insurgency strategy that turned that war around.

By December, General Petraeus was claiming significant progress. "We believe that we have arrested the momentum of the Taliban in many parts of Afghanistan, but not in all," he said.

The general said allied gains are having a psychological as well as tactical impact, but he also acknowledged the Taliban still has free rein in some areas and there is much more work to do. Petraeus commands 98,000 U.S. troops and 48,000 from other coalition countries - about triple the number when President Obama took office two years ago.

The president confirmed in the year-end review that he will begin to draw down the U.S. force level in July.

But he and other NATO leaders, and Afghan President Hamid Karzai, acknowledged at their summit in November that Afghanistan will not be able to take full responsibility for its own security until at least the end of 2014. Even after that, officials expect the country will continue to need some security assistance, as well as more training for its military, police and bureaucrats, and more funding for economic development.

But even with all that effort made and planned by the United States, Afghanistan and their allies, President Obama acknowledged that to achieve real and lasting progress Pakistan must eliminate insurgent safe havens on its side of the border. He said Pakistan has done a lot, but must do more.

Analysts agree. Retired U.S. Army Lieutenant General David Barno, who commanded U.S. troops in Afghanistan from 2003 to 2004, said, "We need to do everything we can to support the Pakistani government in stamping out these safe havens, and we have to be willing to put more pressure on them. And if that includes public pressure, then we have to go there."

Analyst Michael O'Hanlon of the Brookings Institution acknowledges Pakistan's counter-terrorism efforts were hampered by the devastating floods in July, but he says now it is time to act. "I would have to say 2010 was a disappointing year in regard to that particular aspect of the problem, and I would hope 2011 would be substantially better," he said.

On the broader issues of Afghanistan, both experts say for all the attention the December strategy review received it is too soon to really know whether the strategy is working. General Barno said, "I think he, in reality, is going to have to wait until sometime mid to late next summer to analyze what the true results are of the so-called 30,000-troop surge."

Michael O'Hanlon agrees, and adds military gains and progress at improving the local security forces may not be the most important developments in Afghanistan in 2010. He says the NATO decision to continue its commitment at least through 2014 may be more important. "It signals to people in the region that the United States and NATO are not going to be in a hurry to leave next summer. And that may encourage more people to cooperate with us instead of doubting our staying power and hedging their bets and maintaining ties to the insurgents, for example," he said.

The analysts say the coming year will be crucial in determining whether large numbers of ordinary Afghans decide to reject the insurgents, and that is by no means assured. But with U.S. casualties reaching an all-time high of nearly 500 in Afghanistan during the past year, with 5,000 injured, experts say the new strategy will have to show significant results by mid-year to maintain the support of President Obama, the American people and an increasingly divided and budget-conscious Congress.